Zebra Joke: Knock, Knock Flag By: zebrahumor Channel: zebrahumor (More by author: Most viewed, Newest, Most Thumbs) previous next random - Fav + Fav Comment Zebra Humor presents "Knock, Knock", a classic zebra joke told in an experimental format. You need to login to view this link Tags: knock knock | jokes | zebra jokes | Zebra Recommend tagsx +6 Views: 1433 Favorited: 1 Submitted: 08/17/2012 Share On Facebook Remove from favorites Add to favorites Unsubscribe from zebrahumor Subscribe to zebrahumor Subscribe to zebrahumor Unsubscribe from zebrahumor So I see you're using adblock. This site costs a lot of money and time to run. It's also in danger of shutting down since everyone uses adblock and ads used to pay the bills. You can donate here or just post some content so we get new visitors from google (who don't use adblock).